Spencer, J.E; Horvath, R.J (1963). "How does an agricultural region originate?". Annals of the Association of American Geographers53 (1): 74–90. doi:10.1111/j.1467-8306.1963.tb00434.x.
GRDC, Grains Research and Development Corporation. "Growing regions". Grains Research and Development Corporation (in ஆஸ்திரேலிய ஆங்கிலம்). Retrieved 2023-07-01.